JP2018527105A - Powder chamber for air polishing apparatus and air polishing apparatus - Google Patents

Abstract

A powder chamber (10) for an air polisher (90) extending along an axis (c) from a top end (t) to a bottom end (b), the powder chamber (10) comprising at least two walls Portions (11, 12), the first wall portion (11) forms a first angle (α ₁₁ ) with respect to the axis (c), and the second wall portion (12) is The angle measurement direction (md) from the axis (c) to the corresponding wall portion (11, 12) is such that the angle (α ₁₂ ) is 2 and the angles (α ₁₁ , α ₁₂ ) are acute angles, The direction from the top end (t) to the bottom end (b) is positive, the direction from the bottom end (b) to the top end (t) is negative, and the second wall portion (12) is The second angle (α ₁₂ ) is smaller than the first angle (α ₁₁ ), and is disposed below the first wall portion (11).
[Selection] Figure 6

Description

  The present invention relates to a powder chamber for an air polishing apparatus and an air polishing apparatus.

An air polishing apparatus, particularly an air polishing apparatus including a powder chamber, is applied to, for example, a sandblasting technique in the dental field. In this technique, the powder is applied for preventive dentistry, where the powder is a low abrasive powder such as, for example, sodium bicarbonate, calcium carbonate, glycine, or erythritol. In order to avoid tooth damage, the powder has a small particle size with an average particle size ranging from approximately 100 μm to approximately 13 μm.
There are two main ways to remove the powder from the powder chamber. One is to inject air from the top of the powder chamber, and the other is to inject air from the bottom of the powder chamber.

  The second method produces the most accurate powder flow rate and allows the best processing. Nevertheless, there are different problems that arise in the system. That is, the powder flow needs to rise to the suction nozzle, but the difficulty in controlling the powder flow with small particle size (<100 μm) is well known and the powder chamber that is not always possible is completely emptied. The powder flow may exhibit irregularities during the operation.

Patent Document 1 uses a powder chamber having two inclined planes. Such a system may have flow rate fluctuations and a relatively high residue inside the powder chamber. The reason is that the powder may become clogged inside the powder chamber due to self-occlusion.
Patent Document 2 uses a simple cone having two slopes, but in order for the system to operate properly, a powder composed of relatively large particles (approximately 100 μm) must be selected. .
Another solution to overcome the problem is to completely change the powder delivery process by some vibration system as described in US Pat. Such systems are complex and have the problem of using very fine powders.

European Patent No. 2193758B1 European Patent No. 019021B2 British Patent Application No. 2347372A

  It is an object of the present invention to provide an improved emptying action that allows the powder chamber to have a very constant flow rate, good flow control and no or little powder residue inside the powder chamber. An object is to provide a powder chamber for an air polishing apparatus and an air polishing apparatus.

  This object is achieved by the powder chamber for an air polishing apparatus as the first aspect of the present invention and the air polishing apparatus as the fourteenth aspect of the present invention. Additional advantages and features of preferred embodiments of the invention are defined in each aspect cited above.

  The powder chamber for an air polishing apparatus according to the first aspect of the present invention is a powder chamber extending along an axis from a top end portion to a bottom end portion, and at least two wall portions extending along the axis Wherein the first wall portion forms a first angle with an acute angle with respect to the axis along a predetermined angular metering direction, and the second wall portion is below the first wall portion. A second angle which is arranged adjacent to / adjacent to the axis and has an acute angle smaller than the first angle along a predetermined angular metering direction, wherein the predetermined angular metering direction is the apex From the bottom to the bottom end, the direction is positive, and from the bottom end to the top end, the direction is negative.

  The powder chamber of one embodiment extends along the axis from the top end to the bottom end and comprises at least two wall portions, of which the second wall portion is disposed below the first wall portion, The first wall portion is tapered (tapered) with respect to the axis from the top end to the bottom end, and the second wall portion is at least a minimum cross-section of the first wall portion. It has the same maximum cross-sectional area.

  The powder chamber may be filled with a low abrasive powder such as, for example, sodium bicarbonate, calcium carbonate, glycine, or alditol such as erythritol, where the low abrasive powder is to form an air / powder mixture. Rising by pressurized air. For this purpose, the powder chamber is provided with, for example, an air inlet. According to one embodiment, the air / powder mixture is conveyed via an outlet to an air polisher where the air polisher processes the air / powder mixture (added to a water jet or the like). It is like that.

  According to one embodiment, the air and powder are mixed by a combination of vaporizer technology and a vortex. In this case, the venturi tube is located / positioned inside the powder chamber. The venturi opening / inlet is located near the inlet of the powder chamber. The (pressurized) air flow directed from the powder chamber inlet to the venturi inlet / inlet conveys or conveys powder located between or around the inlets. In other words, the powder is sucked into the venturi tube. The particle size of the powder is preferably on average less than about 100 μm, for example in the range of about 5-50 μm, for convenience in the range of about 10-40 μm.

  Usually, the powder is ground and sieved to achieve the desired particle size or particle size. The sieving process makes it possible, for example, to select particles having dimensions that are less than desired or greater than desired (after grinding). This indicates that “average” does not necessarily mean a uniform distribution of particle sizes. Rather, for example, it is possible to sort particles having a size smaller than 5 μm or larger than 70 μm, or sorting particles having a size smaller than 10 μm or larger than 40 μm. According to one embodiment, sorting particles having a size greater than approximately 35 μm, for example (after grinding) does not necessarily mean that most of the particles have a particle size of 35 μm.

As already mentioned, such fine powders do not fall off well. Thus, as is known from the prior art, emptying the powder chamber is unsuccessful and the powder flow exhibits non-uniformity while emptying. This is because the powder height drops from the center of the powder chamber because of suction, but this phenomenon continues until some air passages are formed resulting in a change in powder flow rate.
There is one solution to minimize this phenomenon, which is to form a cone towards the bottom edge of the powder chamber. However, there is a problem with this, that is, the powder is packed by this cone while the powder flow goes to the bottom of the powder chamber, impeding the function of the chamber (so-called self-occlusion). This packing is due to the small size of the powder and the (single) cone geometry.

  Preferably, the powder chamber according to the present invention breaks down the tendency for powder to fall while falling along the direction of gravity, which is the direction from the top end to the bottom end of the powder chamber. This is achieved by the design of the second wall part which is arranged below the first wall part. This second wall portion has an angle that is less than the angle of the first wall portion (hence the second wall portion is more “parallel” to the vertical direction compared to the first wall portion. It is in). Thus, more space is provided for the powder, which prevents or minimizes the stuffing phenomenon.

In order to define an angle, we must consider its measuring direction. If the metering direction is directed from the top to the bottom, the angle is measured as a positive value and vice versa. Positive angles range from 0 ° to less than 90 ° (<90 °) and negative angles range from 0 ° to greater than −90 ° (> −90 °). An angle of +/− 90 ° will mean that each corresponding wall portion no longer “extends” along the axis. Therefore, the angle is a value less / greater than +/− 90 °.
An angle of +/− 0 ° means that the corresponding wall portion is oriented parallel to the axis. Thus, for illustrative purposes and to illustrate the angular metric diagram, if the first angle is, for example, 12 ° and the second angle is 0 ° or −14 °, then “0” is “ Similarly, “−14” is “smaller” than “12”.

  According to one embodiment, the powder chamber comprises a third wall portion that forms a third angle with respect to its axis. Here, the third angle is larger than the second angle, and the third wall portion is disposed below the second wall portion. Accordingly, the third wall portion of the powder chamber (again) is tapered (tapered) with respect to the shaft, respectively, like the first wall portion.

  In other words, the “first volume” of the first wall portion or powder chamber is a cross-sectional area of up to 60% (preferably up to 75%) relative to the inlet cross-sectional area forming the powder chamber opening. Which is at least as large as in a cone / funnel shaped chamber with an angle of 20 ° (up to 70 °).

  The second wall portion or “second volume” of the powder chamber has a cross-sectional area that can be increased or decreased, the increase being in the range of up to 50%, preferably up to 30%. And the reduction is in the range of up to 10% and the average cross-sectional area reduction is at least as large as in a cone / funnel shaped chamber with a 20 ° wall angle. Although the increase in cross-sectional area may be arbitrary, according to a preferred embodiment, the cross-sectional area of the second wall portion remains substantially constant.

  Each of the bottom end of the third wall portion or the bottom end of the powder chamber ("third volume") is compared to the inlet cross-sectional area (compare to the bottom plate described below). , Characterized by a reduction in cross-sectional area of up to 7% (preferably up to 5% or even less), with an average cross-section reduction of 20 ° (maximum 70 °) wall angle Is at least as large as in a cone / funnel shaped chamber.

  The design of the third wall portion results in a very small powder chamber volume at its bottom end. If the venturi tube is located inside the powder chamber, the volume of the powder chamber around the venturi suction system is reduced, creating a constant environment for the venturi system while the powder chamber is completely emptied. Thus, a very constant flow rate is possible.

  Another advantage is that the bottom volume of the powder chamber, in other words the suction volume or the third volume (formed by the third wall portion) is very small, so that the residual powder inside the powder chamber is very low. Less.

  It should be mentioned that the powder chamber is not only used with a venturi system located in the center of the powder chamber. This venturi system is, for example, as known from a centrosymmetric powder chamber. The powder chamber may also be used as a one-sided powder chamber, in which case the Venturi tube remains on one side of the powder chamber, but the principle remains the same.

  According to one embodiment, the first wall portion may be oriented substantially parallel to the axis.

  According to a preferred embodiment, the first wall portion is inclined at a first angle greater than 0 with respect to the axis. Accordingly, the first wall portion is tapered (tapered) with respect to the axis to form a first cone or depression. As already mentioned, cones or depressions are known from the prior art. However, the powder chamber includes a second wall portion along the direction of gravity, and the second wall portion is smaller than the first angle formed by the first wall portion with respect to the axis. With this angle, powder packing is avoided and a very constant flow rate is possible.

According to another embodiment, the first angle and / or the third angle is about 20 ° or more, preferably about 27 ° or more. The second angle is approximately 0 °. This means that the second wall part is oriented substantially parallel to the axis and forms a kind of indentation. The powder chamber is thus designed as a double cone, in which case the two cones are connected by a second wall part designed as a depression.
The first cone formed by the first wall portion tapers from the top end to the bottom end (tapered) and, according to one embodiment, is 50 °, preferably 55. Make an angle greater than °. The same applies to the second cone formed by the third wall portion. The angle of the second cone helps to reduce the amount of residual powder.

  Since the powder chamber has different wall portions, these different wall portions define different volumes. According to one embodiment, the volume of the powder chamber defined by the third wall portion is less than 25% of the total volume of the powder chamber. As already mentioned above, there is very little residual powder inside the powder chamber.

According to another embodiment, the powder chamber comprises a bottom plate, which according to a preferred embodiment is substantially flat. This bottom plate avoids clogging / embolization of the air inlet or nozzle respectively, and the air inlet or nozzle is arranged at the bottom end of the powder chamber. The diameter of the bottom plate is in the range of about 3 mm to 25 mm, preferably in the range of about 4 mm to 20 mm, particularly in the range of about 10 mm. Of course, if the powder chamber is not rotationally symmetric, the aforementioned values can also be transferred to, for example, a rectangular bottom plate or a square bottom plate.
According to another embodiment, the air inlet or nozzle extends inside the powder chamber and in particular extends into the volume formed by the third wall portion. According to this design, the same effect as the above-mentioned bottom plate can be produced. The distance extending between the bottom end of the powder chamber and the nozzle is preferably in the range of approximately 1 mm to 5 mm. According to certain embodiments, the bottom plate can be combined with an air inlet or a nozzle that extends inside the powder chamber. Alternatively, the air inlet or nozzle does not extend inside the powder chamber and therefore the aforementioned distance may be zero.

  According to another embodiment, the length of the second wall portion is approximately 5 mm or more, and the ratio between the length of the first wall portion and the length of the second wall portion is, for example, approximately 10 to 0. .1 and preferably in the range of approximately 5 to 0.5.

  According to another embodiment, the ratio between the length of the second wall portion and the length of the third wall portion is less than 1.

  In another embodiment, the ratio is in the range of approximately 10 to 0.1, for example in the range of approximately 5 to 0.5. This design provides a small third volume, in which case the second volume provides sufficient space to prevent powder packing.

  According to another embodiment, the ratio between the length of the first wall portion and the length of the second wall portion is greater than 1, whereby a high filling volume in combination with an occlusion / embolization prevention effect. Is possible.

Typical design parameters that provide a constant flow rate, good flow rate control and improved emptying action with no or little powder residue inside the powder chamber ( In particular, the length and angle of the wall portion are as follows:
The length of the first wall portion is in the range of approximately 20 mm to 50 mm, preferably in the range of approximately 25 mm, and the length of the second wall portion is in the range of approximately 5 mm to 20 mm, preferably approximately. The length of the third wall portion is in the range of about 10 mm to 20 mm, preferably in the range of about 12 mm, and the first angle is about 20 ° to 70 °. Within the range, preferably within the range of approximately 25 ° to 50 °, particularly preferably within the range of around 30 °, and the second angle is within the range of approximately −70 ° to 20 °, preferably approximately − Within the range of 20 ° to 5 °, particularly preferably within the range of around 0 °, the third angle is within the range of about 20 ° to 70 °, preferably within the range of about 25 ° to 50 °. , Especially preferred Is in the range of approximately 30 °.

  According to another embodiment, the cross section of the powder chamber extending perpendicular to the axis is polygonal, for example, rectangular, square, square, etc. The cross section can also be circular, elliptical, or the like. According to a preferred embodiment, since the powder chamber is rotationally symmetric, its axis may be taken as the central axis.

According to one embodiment, the wall portion is straight in side view (of the powder chamber). Alternatively, the wall portion can be bent or curved or irregular, in particular concave or convex. The angle in this case is in particular an average angle, which is determined by the corresponding tangent. Of course, the powder chamber may also comprise straight wall portions and curved / bent wall portions. If the wall portion is curved or bent, the angle of the wall portion is not constant. However, any infinitesimal “sub-part” of the wall portion meets the angular requirement. This means that the wall portion can be infinitesimal.
As already mentioned, the powder chamber does not necessarily have rotational symmetry. Therefore, the powder chamber does not need to be round in top view, particularly circular, but can be, for example, a polygon or a star. This means that one wall portion may make a different angle with respect to the central axis. Nevertheless, there is at least one region of the wall portion that satisfies the angular requirements such that powder blockage can be effectively avoided.

According to another embodiment, the top end of the powder chamber comprises a sealed portion. This sealing part comprises, for example, a sealing element formed as a ring made of plastic. This sealed portion seals the powder chamber with respect to the container.
In general, the powder chamber is designed / adapted to be positioned and positioned in a container that may be positioned in an air polisher. Preferably, the top end of the powder chamber is also adapted to position and position the insert, in which case the insert comprises, for example, a Venturi tube.

  According to another embodiment, the bottom end comprises an air inlet. The air inlet is designed, for example, as an opening, which is adapted for the nozzle to be arranged or designed / formed as a nozzle. The nozzle is adapted to bring or direct (pressurized) air into the powder chamber.

  The air polishing apparatus according to the present invention includes the powder chamber according to the present invention. Preferably, the air polishing apparatus includes a container, and in this case, the container has a powder chamber disposed therein. Thus, according to one embodiment, the powder chamber and / or container can be easily removed from the air polisher.

The air polishing apparatus includes, for example, a basic apparatus including one or more connection areas. In the connection area (s), the container is arranged and the container is connected to the basic device. The basic device is adapted to provide air to the powder chamber and to draw an air / powder mixture from the powder chamber.
According to one embodiment, for example, a flexible tube is placed in the basic device. The flexible tube includes, for example, a handpiece that includes a nozzle. According to one embodiment, a jet of water can be added to the air / powder mixture in the basic device or nozzle.

According to another embodiment, the powder chamber is adapted to be attached directly to the basic device.
Thus, the powder chamber has the characteristics of a container. Or vice versa.

  Additional advantages and features of the present invention are set forth in the following description of preferred embodiments of the present invention with reference to the accompanying drawings. Obviously, the features and characteristics of the corresponding embodiments may be combined within the scope of the present invention.

It is a figure which shows the diagram of the angle metric used for the definition of an angle. It is a figure which shows the two operation | movement principles of an air polishing apparatus. It is a figure which shows the powder chamber provided with the 1st and 2nd wall part. It is a figure which shows the powder chamber provided with three wall parts. FIG. 4 shows a further embodiment of a powder chamber with three wall portions. FIG. 4 shows a container with a powder chamber having three wall portions. It is a figure which shows a powder chamber, especially a bottom end part. It is a figure which shows the powder chamber provided with a baseplate. It is a perspective view of an air polisher.

FIG. 1 shows a diagram of the angle metric used to define the angle. An axis c is shown extending from the top end t to the bottom end b of the powder chamber (not shown). The first wall portion 11 and the second wall portion 12 extend along the axis c. These wall portions are merely illustrative examples of the angular metering direction md.
The first angle alpha _11, This is so that an acute angle is defined as the angle from the axis c to the wall portion 11. It applies the same definition applies to the second angle alpha ₁₂ formed between the second wall portion 12 and the shaft c. When the angle measuring direction md is directed from the top end t to the bottom end b, the angle is a positive value. When the angle measuring direction md is directed from the bottom end b to the top end t, the angle is a negative value. The positive angle is in the range of 0 ° to less than 90 ° (<90 °) and the negative angle is in the range of 0 ° to greater than −90 ° (> −90 °). Is in range.

FIG. 2 shows two operating principles of the air polishing apparatus, in particular the powder chamber 10. The powder chamber 10 is filled with a powder 1 such as sodium bicarbonate powder, for example, and this powder 1 is raised by pressurized air. When pressurized air enters the interior of the powder chamber 10 via the air inlet 20, the air / powder mixture is conveyed via the outlet 30, for example through a tube etc., to a nozzle where water is added. The
According to the design shown on the left side of the figure, air and powder are mixed by a combination of vaporizer technology and swirls. Therefore, the venturi tube 83 is located inside the powder chamber 10. In other types of designs (shown on the right side of the figure), the air / powder mixture is generated only by swirls.

FIG. 3 shows the powder chamber 10 extending along the axis c from the top end t to the bottom end b. The powder chamber 10 includes a first wall portion 11 and a second wall portion 12. The first wall portion 11 forms a first angle α ₁₁ with respect to the axis c. The second wall portions 12, forms a second angle alpha ₁₂ relative to the axis c.
According to one embodiment, the first angle is 20 ° or more, preferably 27 ° or more. The second angle is smaller than that as seen in the figure. This provides more space for the powder inside the powder chamber. The first wall portion 11 has a length l ₁₁ along the axis c, and the second wall portion 12 has a length l ₁₂ along the axis c to form a corresponding volume.

FIG. 4 shows the powder chamber 10. This is the same as the configuration understood from FIG. However, the powder chamber 10 further includes a third wall portion 13. The second wall portion 12 is oriented substantially parallel to the axis c, thereby forming a recess. In other words, the second angle α ₁₂ is approximately 0 ° and is therefore smaller than the first angle α ₁₁ of the first wall portion 11 and the third angle of the third wall portion 13. The angle α ₁₃ is larger than the second angle α ₁₂ of the second wall portion 12.
By the wall portions 11, 12, and 13 extending along the axis c from the top end t to the bottom end b and having lengths l ₁₁ , l ₁₂ and l ₁₃ along the axis c, respectively The corresponding volume is formed / defined. The figure shows a “double cone” design, wherein the first and third angles α ₁₁ , α ₁₃ are approximately 20 ° or more, preferably approximately 25 ° or more, or approximately 27 ° or more. This means that the apex angle of the cone is about 50 ° or more, preferably about 55 ° or more.

FIG. 5 shows a further embodiment of the powder chamber 10 comprising three wall portions 11, 12, 13 extending along the axis c from the top end t to the bottom end b. The first wall portion 11 forms a first angle α ₁₁ with respect to the axis c, and since this first angle α ₁₁ is greater than 0 °, a first cone is formed. The second angle alpha ₁₂ of the second wall portions 12 a smaller than the first angle alpha _11, in particular because This second angle alpha ₁₂ is a negative value, very effectively self-closure It can be prevented. The third angle α ₁₃ formed by the third wall portion 13 is larger than the second angle α ₁₂ . In fact, the third angle α ₁₃ is positive again (a second cone is formed), like the first angle α _11, and thus a very small third volume is formed. However, this optimizes the effect of emptying the interior and reduces the residual powder inside the powder chamber 10.

FIG. 6 shows the container 80 when used in an air polishing apparatus. The powder chamber 10 is disposed inside the container 80. The powder chamber 10 includes a first wall portion 11, a second wall portion 12, and a third wall portion 13. The powder chamber 10 extends along the axis c from the top end t to the bottom end b, the top end t having a sealing part 40 that seals the first wall part 11 in particular with respect to the container 80, The bottom end b has an air inlet 20. In the embodiment shown in the figure, the insert 82 is arranged at the top end t of the powder chamber 10.
This insert 82 has a venturi tube 83. Outlet 30 is adapted to bring / lead the air / powder mixture to an air polisher (not shown). The wall of the third wall portion 13 does not virtually have an apex, but instead, a flat bottom plate 14 is formed to prevent the air inlet 20 from being blocked by powder inside the powder chamber 10. Yes. 7a and 7b deal with this aspect in more detail.

FIG. 7 a shows the powder chamber 10, in particular the bottom end b and the third wall part 13. The air inlet 20 extends inside the powder chamber 10, in particular into the volume formed by the third wall portion 13, and extends between the bottom end b and the nozzle 22 of the air inlet 20. The distance l ₂₂ at the air inlet 20 is preferably in the range of approximately 1 mm to 5 mm. This prevents the air inlet 20 or nozzle 22 from being plugged / clogged by the powder, respectively.

FIG. 7b shows a powder chamber 10 similar to that illustrated in FIG. 7a. However, the bottom end portion b is formed a bottom plate 14, as its diameter _{d 14,} within the range of about 3mm to 25 mm, there is preferably in the range from about 4mm to 20 mm, embodiments such as in particular approximately 10mm range of about .
The bottom plate 14 avoids the clogging / embolization of the air inlet 20 or the nozzle 22 respectively. As seen in the figure, the nozzle 22 also increases the effectiveness of the bottom plate 14 by extending only a small portion into the volume formed by the third wall portion 13.

  FIG. 8 illustrates the air polishing apparatus 90 including two containers 80 arranged in the basic apparatus of the air polishing apparatus 90. A flexible tube 92 is placed in the basic device. This flexible tube 92 terminates in a handpiece 94 that includes a nozzle 96. If the (inserted) powder chamber is empty, an easily removable container 80 is preferred. Alternatively, only the powder chamber located in the container may be removed to insert a new (full) powder chamber.

1 powder 10 powder chamber 11 first wall portion 12 and the second wall portion 13 third wall portion 14 bottom plate d ₁₄ diameter (bottom plate)
alpha ₁₁ angle (first wall portion)
α ₁₂ angle (second wall part)
α ₁₃ angle (third wall part)
l ₁₁ length of first wall portion l ₁₂ length of second wall portion l ₁₃ length of third wall portion 20 (air) inlet 22 nozzle l ₂₂ distance (nozzle-bottom end)
30 Outlet 40 Sealed portion 80 Container 82 Insert 83 Venturi tube 84 Thread
90 air polishing device 92 flexible tube 94 handpiece 96 nozzle c-axis t top end b bottom end md angle measuring direction

Claims (14)

A powder chamber for an air polisher that is a powder chamber (10) extending along an axis (c) from a top end (t) to a bottom end (b) for an air polisher (90),
A first wall portion (11) forming a first angle (α ₁₁ ) that is acute with respect to the axis (c) along a predetermined angular metering direction (md);
The first wall portion that forms a second angle (α ₁₂ ) with an acute angle smaller than the first angle (α ₁₁ ) along a predetermined angle measuring direction (md) with respect to the axis (c). A second wall portion (12) disposed below (11);
At least two wall portions (11, 12)
The predetermined angle measuring direction (md) is a positive value from the top end (t) to the bottom end (b), and negative from the bottom end (b) to the top end (t). A powder chamber for an air polishing apparatus, characterized by having a value direction. Arranged below the second wall portion (12) that forms a third angle (α ₁₃ ) greater than the second angle (α ₁₂ ) with respect to the axis (c) of the powder chamber (10). The powder chamber for an air polishing apparatus according to claim 1, further comprising a third wall portion (13). The first wall portion (11) of the powder chamber (10) is inclined with respect to the axis (c) at the first angle (α ₁₁ )> 0. A powder chamber for an air polishing apparatus according to 1. The first angle (α ₁₁ ) and / or the third angle (α ₁₃ ) of the powder chamber (10) is 15 ° or more, preferably 25 ° or more. 4. The powder chamber for an air polishing apparatus according to 3. The powder chamber for an air polishing apparatus according to any one of claims 1 to 4, wherein the second angle (α ₁₂ ) of the powder chamber (10) is approximately 0 °. The volume (v ₁₃ ) defined in the third wall portion (13) in the powder chamber (10) is less than 25% of the total volume in the powder chamber (10). The powder chamber for an air polishing apparatus according to any one of 3 to 5. 7. The air polishing apparatus according to claim 1, wherein a length (l ₁₂ ) of the second wall portion (12) of the powder chamber (10) is approximately 5 mm or more. Powder room. The ratio between the length _{(l 12)} and the length of the third wall portion (13) of the second wall portion of the powder chamber (10) (12) _{(l 13)} is less than 1 The powder chamber for an air polishing apparatus according to claim 7, wherein the powder chamber is provided. Than the ratio of 1 between the length of the first length of the wall portion _{(11) (l} 11) and the second wall portion of the powder chamber _{(10) (12) (l} 12) The powder chamber for an air polishing apparatus according to claim 7 or 8, wherein the powder chamber is large.   The powder chamber for an air polishing apparatus according to any one of claims 1 to 9, wherein the powder chamber (10) is rotationally symmetric.   The powder chamber for an air polishing apparatus according to any one of claims 1 to 10, wherein the top end (t) of the powder chamber (10) has a sealed portion (40).   The powder chamber for an air polishing apparatus according to any one of claims 1 to 11, wherein the bottom end (b) of the powder chamber (10) has an air inlet (20).   The venturi tube (83) of the powder chamber (10) is arranged in the powder chamber (10) or on the powder chamber (10). A powder chamber for an air polishing apparatus according to 1.   An air polisher (90) comprising the powder chamber (10) according to any one of the preceding claims.

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